NCERT 8th Class (CBSE) Science: Reproduction

Question: Describe the the process of fertilization in human beings.

Answer: A single egg comes out of the ovary every month, and reaches the fallopian tube. Sperms reach the fallopian tube where a sperm fertilizes the egg. This results in formation of zygote.

Question: Give two differences between a zygote and a foetus.

Answer: The difference is as follows:

Question: Define asexual reproduction. Describe two methods of asexual reproduction in animals.

Answer: When a single parent is involved in reproduction and gametes are not formed, it is called asexual reproduction. Two methods of asexual reproduction are as follows:

Budding: This method is seen in multicellular animals which are highly simple in structure. A small bud develops on the body. The bud develops and starts resembling its mother. After that, the bud gets detached from the mother’s body to begin life as a new individual. Examples: Hydra and sponges.

Binary Fission: This method is seen in unicellular animals, e.g. amoeba. The cell of amoeba divided into two daughter cells. Each daughter cell becomes a new individual.

Question:  Differentiate between internal fertilization and external fertilization.

Answer: The difference is as follows: